纳米二氧化硅粒子的制备及对BSA结构的影响

在碱性条件下水解正硅酸乙酯(TEOS)制备纳米二氧化硅(SiO_2)粒子,并采用同步荧光光谱和紫外可见分光光度法探讨了SiO_2对牛血清白蛋白(Bovine Serum Albumin,BSA)结构的影响。结果显示,SiO_2纳米粒子对BSA的结构没有发生显著的影响,这说明在实验条件下,SiO_2不会改变BSA分子的结构和微环境。     

6-糠氨基嘌呤与牛血清白蛋白相互作用的研究

应用荧光光谱法研究了6-糠氨基嘌呤(KT)与牛血清白蛋白(BSA)相互作用的光谱特性。测定了16℃、28℃和39℃不同温度下的结合常数KA分别为:2.43×104、1.33×104、1.22×104L/mol,结合位点数n分别为:1.08、1.02、1.02。研究结果表明:KT对BSA内源荧光的猝灭机理主要为静态猝灭;探讨了相互作用机理,KT主要以静电作用与BSA相互作用;研究了KT对BSA构象的影响,表明BSA的荧光主要源于色氨酸残基,KT对BSA的构象有影响。     

Enhancement of the Fluorimetric Properties of Some Carboxyl Substituted Anthracenes by Complexation with Bovine Serum Albumin

Abstract

A study has been conducted of the fluorimetric properties of substituted anthracenes, following complexation with bovine serum albuinin(BSA). It was found that although protein binding of the ligands enhances their fluorimetric properties, it fails to do so for their phosphorimetric properties. BSA would serve well in post column reactors for HPLC detectors, but not in pre-column systems.     

氧氟沙星与脲诱导牛血清白蛋白结合的机制研究

摘要 利用荧光光谱和紫外光谱研究了脲（Urea）对牛血清白蛋白（BSA）结构的影响以及氧氟沙星（Oflxacin）与脲诱导的BSA结合的情况。结果显示：Urea诱导BSA变性历经两步、三态过程,且伴随中间态的形成。随着Urea浓度的增大,BSA荧光强度降低并先蓝移（344 nm～336 nm）,后又红移至350 nm。Urea浓度在4.6～5.2 mol/L范围时,Oflx对BSA中间态有强的猝灭作用（KQ=10.46×104 L/mol, Urea 4.8 mol/L）和较大的结合常数（KA=3.8807×105 L/mol, Urea 4.8 mol/L）,但是结合位点数小（n=0.76, Urea 5.0 mol/L）,能量传递效率低（E=0.3002, Urea 4.8 mol/L）。同步荧光光谱显示：Urea诱导BSA去折叠时,Trp-212残基微环境并未发生改变,而Tyr的最大荧光发射峰蓝移,Oflx的加入诱导Trp-212的微环境更具疏水性。Oflx加速了Urea对BSA的失活作用。     

氨基黑10B与牛血清白蛋白作用的光谱法研究

用紫外、荧光、圆二色光谱法研究了氨基黑10B与牛血清白蛋白(BSA)结合反应的光谱特性.结果表明氨基黑10B对牛血清白蛋白的荧光有猝灭作用,其猝灭类型属于静态猝灭;得到了不同温度下的结合常数和结合位点数;利用Gibbs-Helmholtz方程计算得到该猝灭反应的热力学参数,表明氨基黑10B主要以氢键和范德华力与BSA相互作用;圆二色和同步荧光光谱显示氨基黑10B对BSA构象产生了影响.     

铜、锌离子对齐墩果酸与蛋白质相互作用的影响

使用荧光光谱和紫外吸收光谱研究金属离子存在下对齐墩果酸(OA)与牛血清白蛋白(BSA)相互作用的影响.实验结果表明,生理pH值条件下齐墩果酸对牛血清白蛋白的荧光猝灭可能是一个单一的静态猝灭过程.求得了OA与BSA相互作用的结合常数为6.16×103 L·mol-1.Zn2+或Gu2+存在下,OA对BSA的荧光猝灭类型没...     

硫脲壳聚糖Co(Ⅱ)配合物的制备、抑茵活性及与血清白蛋白的作用

合成了硫脲壳聚糖Co(Ⅱ)配合物,运用红外光谱、紫外光谱和差热热重分析对配合物进行了表征,研究了其对大肠杆菌和金黄色葡萄球菌的抑菌性能及与血清白蛋白(BSA)的相互作用.结果表明,硫脲壳聚糖能与Co(Ⅱ)发生配位反应而生成硫脲壳聚糖-Co(Ⅱ)配合物,该配合物的抑菌性能较壳聚糖和硫脲壳聚 糖有显著提高,并能有规律地猝灭...     

Graft Copolymerization of 2-Hydroxy Ethyl Methacrylate onto Chitosan with Cerium (IV) Ion. I. Synthesis and Characterization

Graft copolymerization of 2-Hydroxy ethyl methacrylate (HEMA) on to chitosan was studied using cerium (IV) as the initiator. Optimization of the grafting was worked out by varying the reaction time and monomer concentration. Under controlled conditions, up to 685% grafting with a grafting yield of 92.4% was achieved. FTIR, thermal and XRD techniques were used to confirm the formation of the grafted copolymer. Grafting caused a marginal decrease in the mechanical strength in the dry conditions and a significant decrease under wet conditions for the resultant polymer. The products showed significantly improved swelling at pH 7.4 and pH 1.98 compared to the original chitosan. Grafted polymer showed enhanced Tg and decomposition temperature. The grafting also resulted in improved hydrophilicity as is evident from the contact angle studies of the films.     

磁性壳聚糖微球对牛血清白蛋白的吸附性能

在微乳液体系中, 以戊二醛为交联剂制备了磁性壳聚糖纳米粒子(Fe₂O₃-CS). 采用透射电子显微镜(TEM)、红外光谱(IR)、振动样品磁强计(VSM)等手段对纳米粒子进行表征. 结果表明, 纳米粒子的粒径在40 nm左右, 分散性良好, 具有较好的磁响应性能. 以碳二亚胺(EDC)为活化剂, 研究了Fe₂O₃-CS纳米粒子对牛血清白蛋白(BSA)分子的吸附性能, 并使用原子力显微镜(AFM)、紫外分光光度计(UV)进行表征. Fe₂O₃-CS粒子对BSA 的吸附大致符合Langmuir吸附模型, 298 K时饱和吸附量约为250 mg·g^-1, 吸附常数为0.007 L·mg^-1. 将BSA-粒子分散在不同pH的缓冲溶液中, 研究BSA-粒子复合物的稳定性. 用聚丙烯酰氨凝胶电泳(SDS-PAGE)对结果进行表征, 发现在碱性条件下BSA分子能从磁性粒子表面脱附下来.     

Studies on Permeation of Bovine Serum Albumin (BSA) Through Photo-Modified Functionalized Asymmetric Membrane

UV-initiated photo-modification by hydrophilic functional moieties (viz. acrylic acid, acrylamide) is performed on the photo-responsive Polyether sulfone (PES) membrane. Characterization of the modified membranes has been done by porometry, Fourier Transform-IR (FTIR), contact angle, thermogravimetry, X-ray diffraction and gel permeation chromatography. The grafting of acrylamide is higher compared to acrylic acid, as is evidenced from weight increase, as well as porometry studies. The separation abilities of Bovine Serum Albumin (BSA) have been experimented through all the membranes and results show that modified membranes possess a better separation ability compared to virgin polyether sulfone. The separation order follows the trend: PES-g-(AM) > PES-g-(AA) > PES. pH dependence conformational changes of BSA macromolecule influence the separation. The increase in pH results in the decreasing trend in separation. The water flux recovery ratio (FRR) for the virgin PES membrane is minimum compared to other two grafted membranes.     

蛋白质与刚果红结合反应的研究

研究了酸性溶液中蛋白质(BSA)与刚果红(CGR)的结合反应。BSA与CGR相互作用形成复合物,溶液颜色由蓝色变为红色,最大吸收波长紫移,表明在蛋白质正电荷作用下,CGR由游离态酸色型变为结合态碱色型。测得CGR与BSA的结合最大结合数约为43,符合Scatchard模型。荧光光谱表明,CGR与BSA作用导致BSA荧光猝灭,结合位点为BSA第212位色氨酸残基,相互作用为非辐射能量转移。     

Graft Copolymerization of (Dimethylamino)Ethyl Methacrylate onto Chitosan Initiated by Ceric Ammonium Nitrate

Abstract

(Dimethylamino)ethyl methacrylate (DMAEMA) was grafted onto chitosan using ceric ammonium nitrate as initiator in acetic acid solution. The effects of reaction variables on the grafting percentage and efficiency percentage were investigated, including the amounts of monomer and initiator, reaction time and reaction temperature. The grafted copolymers were confirmed by FTIR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results of TGA and DSC indicated the improvement of thermal stability for chitosan‐g‐poly(PDMAEMA). Solubility test revealed the improved hydrophilicity of grafted chitosan in aqueous acetic acid solution, and its swelled behavior in mixtures of glacial acetic acid and anhydrous ethanol (the ratios of 1:1 and 1:2, v/v). The grafted copolymer possessed amphiphilic structure and exhibited properties of polymeric surfactant.     

加替沙星与牛血清白蛋白的结合反应研究

应用简化的Hummel-Dreyer区带毛细管电泳方法（capillary zone electrophoresis， CZE）研究了牛血清白蛋白与加替沙星分子间的结合作用机制.在位点结合模型的基础上，得到了实用的非线性模拟计算公式，在优选的实验条件下，根据模拟计算公式计算了蛋白质-药物相互作用的结合参数.     

Phenylalanine-Tethered pH-Responsive Poly(2-Hydroxyethyl Methacrylate)

A series of pH-responsive random copolymers comprised of 2-hydroxyethyl methacrylate (HEMA) and tert-butyl carbamate (Boc)-protected phenylalanine methacryloyloxyethyl ester (Boc-Phe-EMA) were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization in N,N′-dimethylformamide (DMF) at 70 °C. The synthesized copolymers were comprehensively characterized using a combination of techniques, including ¹H NMR, FT-IR spectroscopy and size exclusion chromatography (SEC). Reactivity of each monomers towards controlled radical polymerization was evaluated by determining the reactivity ratios by virtue of extended Kelen-Tüdös method at high conversions revealed the higher reactivity of non-modified HEMA (r_HEMA=1.03) in contrast to Boc-Phe-EMA (r_Boc-Phe-EMA=0.48). Furthermore, the expulsion of the Boc-groups resulted copolymers with ionizable pendant primary ammonium and hydroxyl groups. To understand the glass transition behaviours of homo- and co-polymers, differential scanning calorimetric (DSC) measurements were carried out. The effect of HEMA content on the pH-sensitivity of the copolymers in aqueous medium was investigated through turbidity measurements. Finally, the counteranion exchange from trifluoroacetate to chloride provided copolymers with enhanced water solubility and unaltered phase transition pH.     

The effect of external stimuli on the Bovine Serum Albumin adsorption capacity of poly(acrylamide/maleic acid) hydrogels prepared by gamma rays

The effects of external stimuli such as pH of the buffer solution, ionic strength, temperature and the amount of poly-electrolyte monomer in the hydrogel system on the Bovine Serum Albumin (BSA) adsorption capacity of poly(acrylamide/maleic acid) [P(AAm/MA)] hydrogels were investigated. Poly-electrolyte P(AAm/MA) hydrogels with varying compositions were prepared by irradiating acrylamide/maleic acid/water mixtures with γ rays at ambient temperature. Langmuir type adsorption isotherms were observed for all prepared hydrogels. Increase of ionic strength of the buffer solution from 0.01 to 0.1 mol dm⁻³ decreased the adsorption capacity of hydrogels and zero adsorption was observed in the presence of 0.1 mol dm⁻³ Na⁺ and Ca²⁺ ion in the adsorption medium. The adsorption capacity of hydrogels was found to increase from 0 to 120 mg BSA/g dry gel, by changing external stimuli and hydrogel composition.     

用牛血清白蛋白泡沫提取硫酸庆大霉素

研究了用生物表面活性剂牛血清白蛋白（BSA）泡沫提取硫酸庆大霉素的条件及作用机理,并用微生物实验检验庆大霉素的生物活性。结果表明：BSA能替代化学表面活性剂用于氨基糖苷类抗生素的泡沫分离。硫酸庆大霉素的一步提取率为80．2％。     

甲基丙烯酸缩水甘油酯与甲基丙烯酸氯乙酯共聚反应竞聚率的研究

本文合成了甲基丙烯酸缩水甘油酯、甲基丙烯酸氯乙酯和甲基丙烯酸缩水甘油酯与甲基丙烯酸氯乙酯共聚物。用~1H-NMR谱仪测定了共聚物中两种单体的含量。用Fineman-Ross和Kelen-Tilds两种作图方法以及最小二乘法对单体的竞聚率进行估假。结果表明了甲基丙烯酸氯乙酯的竞聚率(r_1)和甲基丙烯酸缩水甘油酯的竞聚率(r_2)分别为r_1=0.712,r_2=1.081。     

光谱法研究氨基己酸与牛血清白蛋白的相互作用

利用荧光光谱、紫外-可见吸收光谱及圆二色（CD）光谱研究了模拟生理条件下的氨基己酸(ACA)与牛血清白蛋白(BSA)的相互作用。 实验结果分析表明,氨基己酸对BSA的内源性荧光具有猝灭作用,属于动态猝灭过程。 计算了2种温度下ACA-BSA体系的结合常数、结合位点数及反应的热力学参数ΔG、ΔH和ΔS分别约为-21.00 kJ/mol、-0.64 kJ/mol和-72.00 kJ/(mol·K),由此推出了二者主要通过氢键和范德华力形成摩尔比为1∶1的复合物。 依据Forster非辐射能量转移理论求得二者之间的结合距离为2.3 nm。 位点取代实验指出氨基己酸主要结合在位点Site I。 CD光谱表明,氨基己酸诱导了BSA分子二级结构微变。     

羟基磷灰石对牛血清白蛋白的吸附特性研究

研究了羟基磷灰石表面电位随溶液PO₄^3-浓度、Ca²⁺浓度、离子强度和pH的变化规律;测定了不同操作条件下牛血清白蛋白在羟基磷灰石上的吸附容量;吸附等温线的测定结果表明该吸附属于Langmuir型;通过对该吸附过程的动力学研究,计算得到的表观活化能和吸附热数值较低,表明该吸附是物理吸附.     

光谱法研究核壳量子点CdTe/CdS与牛血清白蛋白的相互作用

应用荧光光谱、圆二色光谱和紫外吸收光谱等技术研究核壳量子点CdTe/CdS与牛血清白蛋白(BSA)相互作用的结果表明,CdTe/CdS对BSA的荧光猝灭机理为静态猝灭。根据不同温度下量子点对BSA的荧光猝灭作用计算了结合常数、热力学参数,证明了量子点与BSA相互作用力主要是范德华力或氢键作用力。探讨了量子点对BSA构象的影响。